Conventionally, a leakage transformer has been used, for example, as a booster transformer of an inverter circuit for the backlight of a liquid crystal display panel.
In many cases, the casing of a liquid crystal display device, a small-sized computer or the like with a built-in liquid crystal display panel is designed to be small and thin so as not to interfere with space saving. Thus, any device used in the casing of such an apparatus, such as a transformer, is required to be thin and/or narrow.
An example of such a narrow type leakage transformer uses an I-shaped core as the center core extending through the primary and secondary windings and a U-shaped core as the external magnetic path (see, for example, Patent Document 1).
Patent Document 1: JP 2004-31647 A (Abstract, etc.)